Strapping machine



Nov. 9, 1%5 l. G. cRUcKsHANK ET AL 3,216,346

STRAPPING MACHINE 11 Sheets-Sheet 1 Filed 001;. 25, 1963 INVENTORS /f UZ L55 IRA G. CRUCKSHANK PAUL S. ORLANDO DONALD T ARMINGTON BVM?, @m4/w maf ATTORNEYS Nov. 9, 1965 x. G. cRUcKsHANK ET AL 3,216,346

STRAPPING MACHINE 11 Sheets-Sheet 2 Filed OOL. 25, 1963 F/G. 2 M

INVENTORS IRA G, CRUCKSHANK PAUL S. ORLANDO DONALD T. ARMNGTON @www ATTORNEYS NOV- 9, 1965 l. G. cRUcKsHANK ET AL 3,216,346

STRAPPING MACHINE ll Sheets-Sheet 5 Filed 001;. 25, 1965 INVENTORS IRA G. CRUCKSHANK PAUL S. ORLANDO DONALD T ARMINGTON BY @aw ATTWEYS NOV- 9, 1965 l. G. cRUcKsHANK ETAL 3,216,345

STRAPPING MACHINE 11 Sheets-Sheet 4 Filed Oct. 25, 1963 INVENTORS IRA G. CRUCKSHANK PAUL S.ORLANDO DONALD T. ARMINGTON @w24/WMM@ ATTORNEYS Nov. 9, 1965 Filed Oct. 25, 1963 l. G. CRUCKSHANK ETAL STRAPPING MACHINE l1 Sheets-Sheet 5 BYZML' @www INVENTORS IRA G. CRUCKSHANK PAUL S, ORLANDO DONALD T ARMINGTON ATTORNEYS Nov. 9, 1965 Filed oct. 25, 196s NOV- 9, 1965 l. G. cRucKsHANK ET AL 3,216,346

STRAPPING MACHINE Filed Oct. 25, 1965 l1 Sheets-Sheet 7 /az /f NOV- 9, 1965 l. G. cRUcKsHANK ET AL 3,216,346

STRAPPING MACHINE Filed Oct. 25, 1963 11 Sheets-Sheet 8 INVENTORS /4/ IRA G. CRUCKSHANK Q; PAUL S. ORLANDO DONALD T. ARMINGTON BVM ATTORNEYS NOV- 9, 1965 x. G. cRucKsHANK ET AL 3,216,346

STRAPPING MACHINE Filed Oct. 25, 1965 11 Sheets-Sheet 9 INVENTORS IRA G. CRUCKSHANK PAUL S. ORLANDO DONALD T. ARMINGTON ATTORNEYS NOV 9, 1965 l. G. cRucKsl-IANK ET AL 3,216,346

STRAPPING MACHINE ll Sheets-Sheet 10 Filed OCb. 25, 1965 ATTORNEYS NOV 9, 1965 l. G. cRUcKsHANK ET AL 3,216,346

STRAPPING MACHINE Filed Oct. 25, 1963 l1 Sheets-Sheet 11 O| HEIGHT CONTROL MAN. AUTO. 32

DOWN. LIMIT N I INVENTORS IRA s. cRUcKsHANK 358 PAUL SORLANDO DONALD T. ARMINGTON United States Patent O 3,216,346 STRAPPING MACHINE Ira G. Crucltshank, New Britain, Paul S. Grlando, Wallingford, and Donald T. Armington, Southington, Conn., assignors to The Stanley Works, New Britain, Conn., a corporation of Connecticut Filed (Ict. 25, 1963, Ser. No. 319,060 22 Claims. (Cl. 10Q-4) This invention relates to strapping machines of the type conventionally adapted for applying and sealing a loop of metallic strap or ribbon for packaging and the like.

It is a principal aim of the present invention to provide a new and improved strapping machine having particular utility for strapping articles which are extremely hot, such as, for example, coils of sheet metal issuing from a hot rolling process.

It is another aim of the present invention to provide a new and useful strapping machine adapted for strapping an article carried by a conveyor and by which a strap is applied to the article in a plane which is generally parallel to the direction of travel of the article.

It is a further aim of the present invention to provide a new and improved strapping machine which has notable usefulness for applying a strap on an article in a generally horizontal plane.

It is another aim of the present invention to provide a new and improved strapping machine which is adapted for automatically positioning a strap on the article at a given proportion of the distance between the ends thereof, such as one-half that distance or centrally on the article.

It is a further aim of the present invention to provide a new and improved strapping machine which is highly reliable and which can nevertheless be conveniently controlled by a single operator located remote from the mechanical operation of the machine.

It is a still further aim of the present invention to provide a new and improved strapping machine which is completely automatic for applying a tensioned strap to either cold or hot articles with the maintenance of strap tension assured and which performs the complete operation in a minimum time interval.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth, and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a side elevation View, partly broken away and partly in phantom, of an embodiment of the strapping machine of the present invention installed for strapping a conveyor-supported coil of sheet metal;

FIG. 2 is a top plan view, partly broken away and partly in phantom, of the installation of FIG. l;

FIG. 3 is a top plan view, partly in phantom, of a strapping unit subassembly of the strapping machine showing it in position for applying a strap to the coil of sheet metal;

FIG. 4 is an enlarged top plan view, partly broken away, of a locating device of the strapping machine;

FIG. 5 is a side elevation View, partly broken away and partly in section, of the locating device;

FIG. 6 is an enlarged top plan view, partly broken away and partly in phantom, of a portion of the strapping unit and of a seal transfer mechanism of the strapping machine;

FIG. 7 is an enlarged section view, partly broken away, taken substantially along the line 7 7 of FIG. 6 showing operative parts of the seal transfer mechanism in full 3,216,346 Patented Nov. 9, 1965 ICC lines in extended positions and additionally showing portions thereof in phantom in retracted positions;

FIG. 8 is an enlarged section view, partly broken away and partly in phantom, taken substantially along line 8 8 of FIG. 6;

FIG. 9 is an enlarged section view taken along line 9 9 of FIG. 8;

FIG. 10 is an enlarged section View taken along line 10 10 of FIG. 8 showing an operative part in full lines in an extended clamping position and additionally showing a portion thereof in phantom in a retracted position;

FIG. 11 is an enlarged partial top plan view, partly broken away and partly in section, of the strapping unit of FIG. 3;

FIG. 12 is an enlarged side elevation view, partly broken away and partly in section, of the strapping unit;

FIG. 13 is an enlarged section view, partly broken away, taken substantially along line 13 13 of FIG. 1l;

FIG. 14 is a section view, partly broken away, taken along line 14-14 of FIG. 13;

FIG. 15 is an enlarged partial top plan view, partly broken away, of the strapping unit of FIG. 3 showing a strap supporting arm in a retracted position;

FIG, 16 is an enlarged section view, partly broken away, taken substantially along line 16 16 of FIG. 15;

FIG. 17 is a yschematic diagram of an embodiment of a control system of the strapping machine; and

FIG. 18 is a schematic diagram of a timer mechanism of the control system.

Referring now to the drawings in detail and more particularly to FIGS. 1 and 2, an embodiment of the strapping machine of the present invention comprises a rigid stationary frame 10 having two pairs of support posts 12, 14 which are preferably of H-beam construction and I which are shown positioned on opposite sides of a down- Wardly inclined conveyor 16.

Inasmuch as the present invention is notably useful for strapping hot sheet metal coils, an exemplary coil 18 is diagrammatically shown on the conveyor 16 in FIGS. 1 3 to assist in the description of the strapping machine. For this application, the conveyor 16 is preferably powerdriven and subject to remote control by the strapping machine operator to enable him to stop .successive coils on the conveyor at the appropriate position for application of a strap thereto by the strapping machine.

The stationary frame 10 further comprises a primary support platform 15 fixed, as by welding, to the posts 12, 14 to overlie the conveyor 16. The platform 15 has a rectangular structural frame with channels 20 extending transversely of the conveyor 16, channels 22 extending parallel to the conveyor and diagonal support channels 24, 26, 28, 30, 32 and 34.

A strapping unit, generally denoted by the numeral 40, is shown mounted for vertical movement between the posts 12, 14 below the overlying platform 15. The strapping unit 4t) has a frame or deck 42 to which is atlixed a generally circular chute or strap guideway 44 lying in a generally horizontal plane which extends laterally of the axis of vertical or longitudinal movement of the strapping unit 40. Referring to FIG. 1, the frame 42 and chute 44 are, however, slightly inclined so as to be substantially parallel to the conveyor 16, which relationship enables the strapping machine to conveniently apply a strap to the hot coil 18 in a plane which is parallel to the conveyor 16 and, therefore, parallel to the longitudinal end faces of the coil.

The vertical movement of the strapping unit 40' is guided by four pairs of rollers 46, 48 which are adapted to engage the webs and the opposing flanges, respectively, 0f the H-beam posts 12 (FIGS. 1-3) which thereby act as guide tracks, with two pairs of rollers 46, 48 being associated with each H-beam 12 to maintain the parallel relationship between the chute 44 and the conveyor 16. The strapping unit 40 is raised and lowered for longitudinal movement on the H-beam tracks 12, as by a sprocket and chain drive including a pair of drive sprockets 50 and a pair of idler sprockets 54 rotatably mounted on the diagonal channel 24 and a pair of chains 52 received by the drive and idler sprockets and suitably connected at their outer ends to the frame 42 of the strapping unit 40. The sprockets 50 are preferably driven by a three-phase, two-speed, reversible electric motor 56 through a speed reducer 58 having an output shaft 60l driving a pair of meshing gears 62 connected to the sprockets 50. A conventional clutch and brake mechanism 61 is shown in the connection between the motor 56 and speed reducer 58, which in the present embodiment is electrically controlled with the motor whereby the brake quickly terminates the rotation of the sprockets 50 upon the de-energization of the motor 56 and the clutch is engaged to connect the motor 56 and speed reducer 58 upon the energization of the motor. A receptacle (not shown) is preferably secured centrally beneath the diagonal channel 24 to receive the free end of the chains 52 depending from the sprockets 50.

The drive mechanism is therefore adapted to raise and lower the strapping unit 40, preferably at approximately one foot per second, and by switching the three-phase electrical connection to the motor additionally raise the strapping unit 40 at the slower speed of approximately one-half foot per second as it approaches its fully retracted position shown in FIG. l.

Referring to FIGS. 4 and 5, there are provided, adjacent a pair of diagonally opposed corners of the strapping unit 40, a pair of locating devices 66 for ensuring that the strapping unit 40 is appropriately located in its fully retracted position. These locating devices 66 comprise an upright locating pin 68 mounted in a support 70 fixed to the strapping unit frame 42 and a receiver 72 which incorporates a sleeve 74 for snugly receiving the locating pin 68, for which purpose the upper end of the locating pin 68 is tapered. With the strapping unit in its fully retracted position, the upper face of the locating pin support 70 engages the lower face of the receiver 72 whereby the locating device 66 provides for locating the strapping unit 40 along its path of movement and transversely thereof.

Referring to FIGS. l, 2, 6 and 7, a strap seal supply and transfer mechanism 80, mounted to but below the primary support platform 15, provides for positioning a strap seal in alignment with the chute or guideway 44 when the strapping unit 40 is in its fully retracted position whereby the seal is adapted to receive the strap as it is fed forwardly into the chute 44, which strap feed in the present embodiment is accomplished with the strapping unit 40 in its fully retracted position. The seal supply and transfer mechanism 80 includes an automatically orienting seal feed mechanism 82 adapted for feeding seals receivedfrom a vibratory seal hopper 84 via a chute 86 into a chute 88 leading to a magazine 90 (FIG. 7). Referring to FIGS. 6 and 7, a seal transfer mechanism 91 of the seal supply and transfer mechanism 80 is adapted to strip seals successively from the magazine 90 and transfer them into alignment with the chute 44, the chute being generally C-shaped, as seen in FIG. 3, to provide a circumferential opening into which a seal can be transferred by the transfer mechanism 91.

The transfer mechanism 91 includes a pair of bell cranks 92, 94 mounted for pivotal movement about a common axis and operated, by a pair of air cylinders 96, 98, respectively, between retracted positions, partially shown in phantom in FIG. 7, and forward or extended positions, shown in full lines in FIG. 7. The air cylinders 96, 98 are pivotally mounted at their inner ends to a pair of anchor supports 99, 101, respectively, and their connecting rods are pivotally connected to their respective bell cranks. The bell cranks have funnel side portions 100, 102, which, when the bell cranks are in their forward positions, together provide a funnel 103 having a relatively large rectangular inlet opening for receiving the strap being fed to the chute 44, and a relatively small rectangular outlet opening for directing the strap through a seal 104 supported between the bell cranks.

For transferring the seal 104 from the magazine 90, the bell crank 92 has secured thereto an arcuate stripping plate 106 which, during the forward movement of the bell crank 92, provides a gate for the exit opening of the magazine. However, with the bell crank 92 in its fully retracted position, the forward end 107 of the stripper plate 106 is positioned inwardly of the exit opening of the magazine whereby a seal 104 is free to drop onto a permanent magnet support 108 secured to the bell crank 92. Upon subsequent forward movement of the bell crank 92, the stripping plate 106 assists the magnet 108 in transferring a seal 104 from the magazine 90 into alignment with the funnel 103 formed by the bell cranks. As seen in FIG. 7, the seals 104 are preferably preformed with a generally race track shape having an opening on one side thereof, with the seals being automatically oriented by the feeder 82 so that the side with the opening subsequently engages the magnet 108.

The seal supply and transfer mechanism 80 is appropriately supported below the primary support platform 15 by means only partially shown which includes a plurality of depending posts 107 (FIG. 1) welded or otherwise secured to the platform 15 and to which is secured a secondary support platform 111 comprising a pair of channels 112 extending generally parallel to the conveyor 16 and a pair of channels 114 extending transversely of the conveyor.

Welded to the outer ends of the channels 112 is a generally C-shaped ring 115 having a generally L-shaped cross section (FIG. 9) with a depending leg 117 which partially covers the inwardly opening chute 44 when the strapping unit 40 is in its retracted position so as to preclude inadvertent displacement 0f the strap from the chute 44.

Referring to FIGS. 1l-l4, a conventional metal binding strap is adapted to be fed from a coil of strap (not shown) preferably mounted on a motor driven reel, which in cooperation with a feed wheel 122 provides for feeding the strap 120 forwardly into the chute 44. The feed wheel 122 is driven by a reversible rotary air motor 128 and cooperates with a back-up wheel 124 for feeding the strap. To preclude strap slippage the feed wheel 122 is suitably serrated and the back-up wheel 124 is constructed with an intermediate resilient sleeve 126 which is adapted to place a lateral pressure on the strap and thereby keep the strap in driving engagement with the feed wheel 122. The feed wheel 122 and back-up wheel 124 are suitably supported for rotation by shafts 130, 132, respectively, mounted in bearings on an auxiliary frame 134 to which the rotary motor 128 is affixed. The auxiliary frame 134 is pivotally mounted by a pivot pin 136 to a carrier arm 138 which in turn is pivotally mounted by a pivot pin 141 to the frame 42 of the strapping unit 40. Also secured to the auxiliary frame 134 is a generally conventional tensioning and sealing head which includes a sealer 142 operated by an air cylinder 143 and a tension wheel 144 operated by a rotary air motor 145.

Referring particularly to FIG. 1l, the strap 120 is fed by the feed wheel 122 through a funnel 146 mounted in the auxiliary frame 134 and through a passageway 148 in the tensioning and sealing head which also receives the tension wheel 144. The strap 120 thereafter feeds between the open jaws (not shown) of the sealer 142, through the funnel 103 of the seal transfer mechanism 91, through a seal 104 retained by the extended bell cranks 92, 94 and into the Chute 44. The chute theres Upon forms the strap into a loop having an overlapping inner lap extending adjacent a serrated base 150 of the tensioning and sealing head 140, between the open jaws of the sealer, through the funnel 103 and seal 104 again and to approximately six inches past the seal 104 whereupon the strap feed is terminated.

After the forward feed of the strap is completed and after the bell cranks 92, 94 have been withdrawn to leave the seal 104 freely supported on the overlapping portions of the strap, a second seal transfer mechanism 156 (FIGS. 6, 8-10) is operated to angularly displace the seal 104 and the formed loop of strap in the chute 44 and thereby position the seal between the jaws of the sealer 142. The transfer mechanism 156 includes a clamping device 157 having a pair of jaws 158, 160, with the jaw 160 being pivotally mounted with respect to the jaw 158 and retractable therefrom by an air cylinder 162 pivotally mounted on the clamping device. While the strap is being fed forwardly by the feed wheel 122, the jaw 160 is retained in its retracted position to allow the strap to pass freely therebetween; however, upon completion of the forward feed of the strap the air cylinder 162 is operated to clamp the overlapping portions of the strap between the jaws 158, 160.

The clamping device 157 is then shifted by an air cylinder 172 for movement along the periphery of the loop of strap whereby the seal is angularly shifted with the loop of strap to position the seal between the jaws of the sealer 142. To enable the clamping device 157 to move laterally and thereby proceed along the arcuate loop of strap, a connector 168 fixed to the end of a rod 170 of the air cylinder 172 slideably receives a laterally extending pin 166 of the clamping device 157. A compression coil spring 173 encircling the pin 166 provides for biasing the clamping device 157 to the left, as seen in FIG. 10, to maintain the jaw 158 out of the path of the strap 120 as it is fed forwardly into the chute. Additionally, the air cylinder 172 is mounted for pivotal movement on the secondary platform 111 by a pivot pin 180 to automatically align the clamping device 157 with the chute 44. In order to control the travel of the air cylinder rod 170 and therefore the extended position of the clamping device 157, there is provided a plate 182 which is fixed to the connector 168 and which has an elongated slot 184 that receives the pivot pin 180.

Therefore upon actuation of the air cylinder 162 for clamping the overlapping portions of the loop of strap, the jaw 158 will be forced laterally against the compression spring 173 into engagement with the strap. The air cylinder 172 is then operated, to the left as seen in FIG. 8, whereby the loop of strap and seal 104 are angularly displaced, clockwise as seen from above the strapping machine, to position the seal 104 between the jaws of the sealer 142, which operation is coordinated with automatic relatively low speed withdrawal of the strap by reverse rotation of the rotary air motor 128 with relatively low air pressure and by reverse rotation of the strap reel. The air cylinder 162 is then operated to unclamp the strap and the air cylinder 172 is operated to withdraw the clamping device 157.

Upon the completion of the transfer of the seal to the sealer 142 and prior to the withdrawal of the clamping device 157, the sealer air cylinder 143 is operated with relatively low air pressure which is thereafter maintained to partially crimp the seal on the inner lap of the overlapping portions of strap and thereby prevent the inner lap of strap from being withdrawn from the seal and retain the seal in the jaws of the sealer. Consequently after the clamping device 157 is withdrawn, the strapping unit 40 is in a stand-by condition preparatory for strapping a coil on the conveyor 16. With a coil in appropriate position below the strapping unit 40, the strapping unit is lowered about the coil to a strap-apply position with the chute 44 aligned with the center of the coil 18 whereby a strap is applied midway between the ends of the coil. Where, however, more than a single strap is to be applied, it may be preferred that the straps be equally spaced along the coil, as for example where two straps are to be applied to the coil, these straps may be preferably located one-third and two-thirds the distance, respectively, between the ends yof the coil.

After the strapping unit is lowered to its strap-apply position, a plurality of strap supporting arms 200 are pivoted inwardly, preferably into contact with the sides of the coil 18, whereby when the strap is subsequently tensioned about the coil it will be guided laterally from the chute by the supporting arms 200 into engagement with the coil. Referring particularly to FIGS. 15 and 16, each supporting arm 200 is pivotally mounted to the frame 42 of the strapping unit 40 by a pivot pin 202 and has a retracted position below the strapping chute 44 and out -of the central opening thereof. The supporting arm 200 is mounted by a collar 206 welded to the arm which receives a pair of bushings 204 mounted on a pivot pin 202. Each supporting arm 200 is independently operated by a rotary air motor 208 whereby all the arms 200 are adapted to engage the coil even though it is not centered in the opening of the chute 44. The air motor 208 has a drive shaft 210 with a drive sprocket 212 which is connected for extending and withdrawing the arms 200 by an endless chain 214 and a driven sprocket 216 which is xed to the collar 206.

The carrier arm 138 is operated in part by an air cylinder 220 which is pivotally mounted by a pivot pin 222 to the strapping unit frame 42 and which has a piston rod 224 pivotally connected to -the carrier arm 138 by a pivot pin 226.

With the strap supporting arms 200 in contact with the coil 18 the strap is retracted, initially by reverse rotation of the rotary air motor 128 to withdraw the strap from the chute into engagement with the coil 18. This inward movement of the strap creates an inward force on the tensioning and sealing head whereby the carrier arm 138 is displaced inwardly until the serrated base 150 of the tensioning and sealing head 140 clamps the s-trap against the coil 18, it being understood that as the strap is retracted the outer lap of strap is withdrawn through the seal 104 now retained by the jaws of the sealer 142 and the inner lap of strap is held by the low pressure crimping of the sealer 142. Upon inward movement of the carrier arm 138, the auxiliary frame 134 including the tensioning and sealing head 140, move inwardly, with the auxiliary frame 134 automatically assuming a pivotal position on the carrier arm 138 whereby the position of the strap 120 on the auxiliary frame extends tangentially o-f the coil 18.

The initial withdrawal of the strap by the feed wheel 122 places the loop of strap on the coil under relatively low tension due to the relatively high-speed, low torque characteristics of the feed wheel drive motor 128. A relatively high tension is thereafter placed on the strap by the tension wheel 144 to create the desired tension on the strap about the coil 18. In order to create a suflicient clamping force on the inner lap of strap for retaining it from withdrawing from the seal 104 under the high tension provided by the tension wheel 144, the carrier arm 138 is rst forced inwardly by the air cylinder 220 and thereby acts to substantially increase the clamping -force on the inner lap of strap resulting from the engagement of the serrated base therewith. This lateral force on the coil which is preferably about 1200 pounds is opposed by the frictional force between the coil and conveyor and by the strap supporting arms 200, whereby the coil is not shifted laterally within lthe chute opening due to the clamping force on the inner lap of strap.

With the strap tensioned about the coil 18, the air cylinder 143 of the sealer 142 is operated by high pressure air to complete the sealing of Ithe strap about the coil and, in a conventional manner, to shear the loop of strap from the unused strap in the machine. The strapping having been accomplished, the strap supporting arms 200 and the carrier arm 138 are withdrawn by their respective air motors 208, 220, and the strapping unit 40 is raised by the electric motor 56 to relocate the strapping unit in its retracted position.

Operation summary Thus the sequence of operations of the strapping machine are as follows. With the strapping unit 40 in its retracted position, the air cylinders 96, 98 are operated to extend the bell cranks 92, 94, respectively, and thereby strip a seal from the magazine 90 and displace it into alignment with the chute 44 and the strap funnel 103 formed by the bell cranks. The air motor 128 is then operated for feeding the strap from the tensioning and sealing head 140, through the funnel 103 and seal 104, around the chute, and through the funnel and seal a second time whereupon the forward feed is terminated with the free end of the strap between the open jaws 158, 160 of the clamping device 157. The air cylinders 96, 98 are -then operated to retract the bell cranks 92, 94, respectively, and the air cylinder 162 is operated to clamp the overlapping portions of the strap with the jaws 158, 160. The air cylinder 172 is then operated in conjunction with reverse operation of the air motor 128 and the reel motor to angularly displace the formed loop of strap and the seal and there-by position the seal 104 between the jaws of the sealer 142. The lair cylinder 143 of the sealer 142 is then actuated by low pressure to provide initial crimping of the seal on the inner lap of strap, which low pressure crimping is maintained until sealing is subsequently accomplished by high pressure operation of the sealer 142. Accompanying the low pressure operation of the sealer, the 4air cylinder 162 of the clamping device 157 is operated to withdraw the movable jaw 160 and the air cylinder 172 is operated to retract the clamping device 157.

At this point the strapping unit is in a ready state preparatory for strapping a coil 18 when it is positioned therebelow, whereupon the strapping unit operating motor 56 is energized to lower the strapping unit 40 to its strapapply position. The rotary air motors 208 are then operated to pivot the support arms inwardly into contact with the coil 1S and the rotary air motor 128 is driven to withdraw the .strap and thereby provide initial tensioning of the strap about the coil 18 accompanied by inward movement of the carrier arm 138, for which purpose the operating air cylinder 220 of the carrier arm 138 is vented to the atmosphere. The air cylinder 220 is then operated to securely clamp the inner lap of strap against the coil and the rotary air motor 145 is operated to place the strap under appropriate tension. The binding of the coil is completed by operation of the sealer 142 with high pressure to effect sealing of the loop of strap and shearing of the sealed loop from the unused strap.

Upon completion of the sealing, the air cylinder 143 of the sealer 142 is connected to exhaust whereby the sealer jaws are withdrawn to release the seal, and the air cylinder 220 and the air motors 208 are operated to withdraw the carrier arm 138 and the strap supporting arms 200, respectively. The strapping unit 40 is then raised by the electric motor 56 to replace the strapping unit in ,its fully retracted position.

Electrical control system FIG. 17 is a schematic diagram, using the NEMA and JIC electrical symbol standards, of an embodiment of an electrical control system for operating the strapping machine. In this schematic the contacts, micro switches and manually operable switches are shown as they would normally be with the strapping unit 40 in its fully retracted position and with the circuit de-energized.

Generally the electrical control system is adapted, upon the strapping unit 40 reaching its fully retracted position, to automatically complete t-he following steps:

(l) Operate the bell crank actuating cylinders 96, 98 to transfer a seal from the magazine into alignment with the chute 44.

(2) Operate the rotary feed motor 128 to feed the strapping forwardly.

(3) Operate the jaw actuating cylinder 162 to clamp the loop of strap and operate the cylinders 96, 98 to withdraw the bell cranks 92, 94.

(4) Operate the cylinder 172 to transfer the seal angularly to the jaw of the sealer 142 and concomitantly operate the air motor 128 in reverse.

(5) Operate the sealer actuating cylinder 143 to lightly crimp the seal on the inner lap of strap.

(6) Operate the cylinders 162 and 172 to Withdraw t-he jaw 160 and clamping dev-ice 157.

With a coil 18 located appropriately under the strapping unit 40, the electrical control system, upon manually actuation of a cycle control switch 300, is adapted to automatically complete the following steps:

(7) Energize the electric `motor 56 to lower the strapping unit 40 t-o a predetermined position relative to the ends of the coil.

(8) Operate the rotary air motors 208 to extend the strap supporting arms 200` into engagement with the coil.

'(9) Operate the air motor 128 in reverse to withdraw the strap from the chute into engagement with the coil.

(10) Operate the air cylinder 220 to clamp the strap against the coil, and operate the air motor to tension the strap on the coil.

(l1) Operate the sealer cylinder 143 to seal the loop of strap and shear the sealed loop from the unused strap.

( l2) Operate the air motors 208 and the air cylinder 220 to withdraw the strap supporting arms 200 and carrier arm 138.

(13) Energize the motor 56 to raise the strapping unit 40, rst at relatively high speed and then at a relatively low speed as it approaches its fully retracted position where the aforementioned steps numbered 1-6 are automatically performed.

The control system includes a number of relays having relay coils designated A through R which operate the relay contacts similarly prefixed in the schematic diagram and also operate additional contacts (not shown) for controlling, upon energization of the relay coil unless otherwise indicated, the operation of the various air motors and air cylinders and the electric motor 56 of the strapping machine as follows:

Relay Coil: Ready operation A Operates air cylinders 96, 98 to extend bell cranks 92, 94. B ...Operates rotary air motor 128 forwardly. C .Operates air motor 162 to extend jaw G -Operates strap feed motor 128 in reverse with relatively high pressure.

H .Operates air motors 208 to extend strap supporting arms 200.

I .Operates air motors 208 when de-energized to withdraw strap supportlng arms 200.

9 Relay Coil: Ready operation J Operates air cylinder 220 when deenergized to withdraw carrier arm 138. K .Operates air cylinder 220 to clamp the inner lap of strap to the coil. L Operates air motor 145 to drive tension wheel 144. M Operates sealer air cylinder 143 under high pressure to seal strap. N .Operates to energize the motor 56 for raising the strapping unit 40 at a relatively high speed of approximately one foot per second.

O Operates to energize the motor 56 for raising the strapping unit 40 at a relatively low speed of approximately one-half foot per second.

P Operates to energize the motor 56 for lowering the strapping unit at the relatively high speed of approximately one foot per second.

Q -Operates to energize a strap coil reel motor (not shown) for feeding strap to the strapping machine.

R Operates to energize the strap coil reel motor for withdrawing strap from the strapping machine.

A few -remaining relays in the electrical control system are used in conjunction with a number of microswitches, pressure switches and manually operable switches for controlling with the aforementioned relay coils A through R the operation of the strapping machine. Included therein is a master relay having a relay coil X which is adapted to be energized by a start button 302 for activating the control system circuit, which activation may be conveniently indicated by a light 306 and readily terminated by an emergency stop button 304.

A timer mechanism 309, diagrammatically shown in FIG. 18, is used for automatically controlling the strapapply position of the strapping unit 40 by controlling the time period the strapping unit is lowered from its fully retracted position. The timer mechanism 309 incorporates a conventional constant speed drive motor 310 having an output shaft 312 which is adapted to drive an operating shaft 316 of an adjustable timer 317 at relatively high and low speeds by drive trains 318, 320 having clutches 322, 323, respectively. In the present embodiment, the drive trains 318, 320 are such that the shaft 316 is driven at twice the speed by the drive train 318 as it is by the drive train 320. Additionally, the timer 317 is adjusted so that if it were driven entirely by the low speed train 320 the time period provided thereby would be equal to the time it would take the strapping unit 40 to be lowered by the motor 56 from its fully retracted position to a hypothetical position where the strapping unit 4t) would be located for applying a strap to the coil 18 at its lower edge. This hypothetical position of the strapping unit 40 is, however, unobtainable because of interference between the strapping unit and the conveyor 16, for which purpose the maximum downward travel of the strapping unit 40 is limited by a microswitch 314. A pair of timer drive train activating coils TV-a and TV-b (FIG. 17) are provided for controlling the engagement of the low speed train clutch 323 and the high speed train clutch 322, respectively, and the timer 317 is adapted, upon completion of its controlled period, to break the circuit through the contacts TV-1 to de-energize the relay coil P and to complete the circuit through the contacts TV-2.

A microswitch 324 is provided in the control circuit for controlling the energization of the activating coils TV-a and TV-b and therefore the engagement of the 10 clutches 323, 322, respectively. This switch 324 is actu= ated to de-energize coil TVa and energize coil TV-b by a sensing bar 326 when the sensing bar engages the top surface of the coil 18 and is pivoted upwardly thereby as the strapping unit 40 moves downwardly about the coil. The sensing bar 326 has a normal generally horizontal pivotal position which provides that it engages the coil and the switch 324 is thereby actuated as the strapping unit 40 is lowered through the position Where it would be located for applying a strap to the coil at its upper edge. As a result, the timer 317 is driven at twice the initial speed during the period the strapping unit 40 is below the upper longitudinal face of the coil, and accordingly the lowering of the strapping unit will be terminated by the timer 317 when it is midway between the ends of the coil 18.

Timer activating coils TY and TZ for two additional timers (not shown) are used in the control circuit for initiating timing cycles which operate to delay the actuation of the contacts prefixed with TY and TZ, respectively. Upon reference to FIG. 17 it will be seen therefore that the timer activating coil TY is provided for controlling the period of energization of the relay coil B and therefore the period of forward operation of the feed motor 128 and as a result the length of strap along the chute 44. The timer activating coil TZ is provided for controlling a heat soaking period during which the loop of strap tensioned about the hot coil 18 has an opportunity to reach the temperature of the coil and subsequent to which the relay coil M is energized to seal the strap. Consequently, upon the subsequent cooling of the hot coil and strap, the initial strap tension on the coil is substantially retained.

Additional microswitches 330, 332, 334, 336, 338, 340, 342, 344 and 346 are provided for controlling the sequence of operations of the strapping machine. The microswitch 330 is actuated to the position shown in FIG. 17 when the strapping unit 40 reaches its fully retracted position to initiate the sequence of operations performed with the strapping unit in that position. The microswitch 332 is actuated to complete the circuit to the relay coil E when a seal has been received between the jaws of the sealer 142, whereupon the sealer actuating cylinder 143 isv operated by low air pressure to provide the light crimping of the seal on the inner lap of the strap. The microswitch 334 is actuated when the jaws of the sealer 142 are closed and therefore after sealing is complete to break the circuit to the coils G through M, R and TZ. The microswitch 336 is actuated by the bell cranks 92, 94 when they are fully extended to energize the circuit to the coils TY and B and thereby commence the feed timing period and the forward feed of the strap, respectively. The microswitch 338 is actuated as the strapping unit 40 is raised through a position approaching the fully retracted position whereby the relay coil N is energized and the relay coil O is de-energized to reduce the upward speed of the strapping unit 40 as it approaches its fully retracted position. The remaining microswitches 340, 342, 344 and 346 are closed by the carrier arrn 138 and the strap supporting arms 200 when they are fully withdrawn t0 prevent raising the strapping unit 40 prior to their complete withdrawal.

Two pressure responsive switches 359 and 352 are provided in the control system for respectively de-energizing the relay coil D and for energizing the coils TZ, K and L. The pressure switch 350 is operated by the slight build-up in air pressure which results when the air cylinder 172 is fully extended and therefore when the angular displacement of the loop is complete whereupon the low pressure reverse feed of the strap is terminated by the de-energization of relay coil D. The pressure switch 352 is actuated by the slight build-up in pressure which results when the rotary air motor 128 stalls and therefore when the loop of strap is tensioned by the motor 128 on the coil.

With this control system, the strapping operation is made fully automatic once the cycle control button 300 is actuated, with the total cycle in the present embodiment taking approximately 30-35 seconds including a heat soaking period of approximately seconds immediately prior to the sealing operation.

For manual control of the raising and lowering of the strapping unit there are additionally provided three manually operable switches 354, 356 and 35S. The switch 354 is a two position switch having manual and automatic positions which may be individually selected as desired. With the switch 354 in the manual position, the strapping unit 40 may be lowered as desired by the switch 356 or raised as desired by the switch 35S. Additionally, a manually operable switch 360 is provided for manual control of the application of the strap land is particularly useful in conjunction with the manual lowering of the strapping unit for the application of the strap at a position different than that provided by the automatic control.

It is also contemplated that when the strapping machine is used for strapping articles supported on a poweroperated conveyor, a safety switch (not shown) will be provided in the conveyor motor circuit which is actuated in conjunction with the switch 330 to prevent inadvertent operation of the conveyor when the strapping unit 40 is not in its fully retracted position.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

We claim:

1. A strapping machine for binding with a tensioned strap comprising, la stationary frame, a strapping unit mounted for longitudinal movement on the stationary frame, drive means for shifting the strapping unit longitudinally on the stationary frame between a retracted position .and an extended strap-apply position; said strapping unit comprising .a strap gnideway for guiding the strap into a -laterally extending loop and strap feeding and tensioning means for feeding a free end of strap from a supply thereof along the guideway and thereby form a loop with overlapping porti-ons and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby; sealing and shearing means for crimping a strap Seal onto the overlapping portions of the tensioned strap and for shearing the sealed loop of strap from the remaining supply of s-irapg and control means for automatically controlling the strap-apply position of the strapping unit for locating the tensioned loop on the article at a position which is a predetermined proportion of the distance between the longitudinal ends of the article irrespective of the dimension between the longitudinal ends of the article.

2. A strapping machine for binding with a tensioned strap comprising, a stationary frame, a strapping unit mounted for substantially vertical longitudinal movement on the stationary frame, and motor means for raising and lowering the lstrapping unit on the stationary frame between retracted and strap-apply positions; said strapping unit comprising a strap guideway for guiding the strap into a laterally extending loop, strap feeding and tensioning means for feeding a free end of strap from a supply thereof along the guideway and thereby form a loop and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby, sealing and shearing means for sealing the overlapping portions of the tensioned strap and for shearing the sealed loop of strap from the remaining supply of strap, and strap support means for laterally guiding the loop of strap inwardly from Ithe guideway into engagement with said article, said strap support means being laterally retractable from the article t-o enable the .strapping unit to be lowered thereon.

3. The strapping machine of claim 2 wherein the strap ticle, and means for independent pivotal operation of the arms.

4. A strapping machine for binding with a tensioned strap comprising a .stationary frame, a .strapping unit mounted for substantially vertical longitudinal movement on the stationary frame and motor means for raising and lowering the strapping unit on the stationary frame between retracted and strap-apply positions; said strapping unit comprising a strap guideway for guiding the strap into a laterally extending loop, strap feeding and tensioning means for feeding a free end of strap along the guideway and thereby form a loop with overlapping portions and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby, sealing means for sealing the overlapping portions of the tensioned strap, and strap support means for laterally guiding the loop of strap inwardly from the guideway int-o engagement with said article, said strap sup-port means being l-aterally pivotable into engagement with the article; and control means automatically operable with the strapping unit in the strap-apply position for operating the strap feeding and tensioning means for withdrawing the strap and thereby tension the loop of strap about the article, and for subsequently operating the sealing means for sealing the overlapping portions of the tensioned strap.

5. The strapping machine of claim 4 wherein the control means comprises means for providing a heat soaking period for `the loop of strap prior to the sealing of the strap by the sealing means.

6. A strapping machine for binding with a tensioned strap comprising a stationary frame, a strapping unit mounted for ylongitudinal movement on the station-ary frame, motor drive means for shifting the strapping unit longitudinally on .the stationary fra-me between a retracted position and an extended strap-apply position, said drive means being operable for shifting the strapping unit to its strap-apply position at a constant rate; said strapping unit comprising a strap guideway for guiding the strap into 'a laterally extending loop, strap feeding and tensioning means for feeding a free end of strap along the guideway and thereby lform 4a loop and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby; and control means for automati-cally controlling the strap-apply position of the strapping uni-t comprising timing means providing a time variable period of operation of the drive motor at said constant rate which varies with the longitudinal dimension of the article, and means for sensing the longitudinal dimension of the article for controlling the variable time period provided by the timing means.

7. The strapping machine of claim 1 wherein the drive means is operable for extending the strapping unit longitudinally on the stationary Vframe .at a constant rate, and wherein the automatic control means includes timing means `for varying the period of operation of the drive means .at said constant rate in accordance with the dimension between the longitudinal ends of the article.

8. The strapping machine of claim 7 wherein the timing means comprises .a rotary element which terminates the operation of the drive means at said constant rate after a xed angular displacement, lirst means for driving the rotary element at a first -angular rate `du-ring an initial extension of the strapping unit, means for sensing the longitudinal dimension of the article, and second means activated` by the sensing means for Vautomatically driving the rotary element :at -a second angular rate.

9. In a strapping machine for binding with a tensioned strap, -a strapping unit comprising `a strap guideway for -guiding a strap into a generally horizontally extending loop, a carrier arm pivotally connected to the strap guideway for generally horizontal pivotal movement, a strap feeding and tensioning means mounted on the carrier arm adapted for feeding a free ,end of strap along the guideway and thereby form a loop of `strap with overlapping portions and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby, sealing means pivotally mounted on the carrier arm for sealing the overlapping portions of the tensioned strap, and strap supporting arms pivotally mounted on the strapping unit for generally horizontal pivotal movement into engagement with the article for guiding the loop of strap inwardly from the guideway.

10. A strapping machine for binding with a tensioned strap comprising, a stationary frame, a strapping unit mounted for longitudinal movement on the stationary frame, motor means roperable for driving the strapping un-i-t l-ongitudinally on the stationary frame between a retracted position and an extended strap-apply position; said strapping unit comprising a strap guideway for guiding the strap into a laterally extending loop, strap feeding and tensioning means for feeding a free end of stra-p along the guideway and thereby fo-rm a loop with loverlapping portions and for subsequently withdrawing the strap fortensioning the loop about an article encircled thereby, and control means for automatically controlling the strap-apply position of the strapping un-it comprising, means for sensing the longitiudinal dimension of the article, and timing means for controlling the period of operation of the motor means, said control means being operable to effect termination of the operation of the motor means with the strapping unit at a strap-apply position which is a predetermined portion of the distance between the longitudinal ends of the article.

11. A strapping machine for binding with a tensioned strap comprising, a stationary frame, a strapping unit mounted for longitudinal movement on the stationary frame, means for shifting the strapping unit longitudinally on the stationary frame between a retracted position and an extended strap-apply position; said strapping unit comprising a strap guideway for guiding the strap into a later-ally extending loop, strap feeding and tensioning means for feeding a free end yof strap along the guideway and thereby form a loop with overlapping portions and for subsequently withdrawing the strap for tensioning the loop labout `an article encircled thereby; and seal transfer means mounted for operative association wit-h the strap guideway for feeding a strap seal into alignment with the strap guideway for receiving the free end of strap as itis fed forwardly by the strap feeding `and tensioning means.

12. The strapping machine of claim 11 wherein the seal transfer means comprises a seal magazine and a seal stripping `device operable to transfer seals successively from the seal magazine into alignment with the strap guideway.

13. The strapping mac'hine of claim 11 wherein the seal transfer means comprises a pair of pivotally mounted arms operable between retracted positions and fully extended positions, a seal magazine, said arms in their fully extended positions forming a funnel aligned with the strap guideway for receiving the free end of stra-p, and a seal striping means operable to transfer seals successively from the seal magazine into alignment with said funnel whereby the free end of strap is directed by the funnel through the seal.

14. The strapping machine of claim 13 wherein the seal stripping means is connected to one of said arms and is operable to transfer a seal from the magazine into alignment with the funnel upon pivotal operation of said one arm to its extended position.

15. T-he strapping machine of `claim 11 wherein the strapping unit further comprises sealing means for crimping la strap seal onto the overlapping portions of the tension strap, and wherein the seal transfer means further comprises seal positioning means for displacing a seal on the strap into position for crimping by the sealing means.

16. The strapping machine of claim 15 wherein the seal positioning means comprises means for clamping the overlapping portions of the loop of strap and means for shifting the clamp laterally to shift the loop and seal and thereby position the seal into position for crimping by .the sealing means.

177. A strapping machine for binding with a tensioned 'strap comprising, a stationary frame, a strapping unit mounted for longitudinal movement on the stationary frame, means for :shifting the strapping unit longitudinally on the stationary frame between a .retracted position and an extended strap-apply position; said strapping 'unit comprising a strap guideway for guiding the strap into a laterally extending loop, strap feeding and tensioning means for feeding a free end of strap along the guideway and thereby form a loop with overlapping portions and for subsequently withdrawing the strap for tensioning the loop Iabout an article encircled thereby, and sealing means for crimping a seal onto the Ioverlapping porti-ons of the tensioned strap; seal transfer means mounted for operative association with the strap sealing means for feeding a 'strap seal to the Sealing means, and control mean-s for actuating the sealing means for :lightly crimping the strap seal onto the inner lap of t'he overlapping porti-ons of stra-p.

18. In a strapping machine for -binding with a tensioned strap, a strapping unit comprising a strap guideway for guiding a strap in-to a laterally extending loop, a carrier arm pivotally connected t-o the strap guideway for lateral pivotal movement, strap feeding and tensioning means mounted on the carrier arm adapted for feeding a free end of strap along the guideway and thereby form a loop of strap with yoverlapping portions and for subsequently withdrawing the `strap for tensioning the loop about anarticle encircled thereby, sealing means pivotally mounted on .the carrier arm for sealing the overlapping portions of the tensioned strap, and means for pivotally positioning the carrier arm.

19. A strapping machine for binding with a tensioned strap compris-ing, a stationary frame, a strapping unit mounted for longitudinal movement on the .stationary frame, and means for shifting the strapping unit longitudinally on the stationary frame between a retracted position and an extended strap-apply position; said strapping unit comprising a strap guideway for guiding the strap into a laterally extending loop, strap feeding and tensioning means for feeding-a free end of strap along the guideway from a supply thereof and thereby form a loop with overlapping portions and for subsequently withdrawing the strap for tensioning the loop about an article encircled thereby, sealing and shearing mean-s for crimping a strap seal onto the overlapping portions of the tensioned strap and for shearing the sealed loo-p of strap from the remaining supply of strap, and means mounting the sealing :and shearing means for lateral movement fr-om a retracted position inwardly to -adjacent the article comprising a first carrier arm pivotally connected to the strap guideway for lateral movement inwardly from a retracted position, and means pivot-ally mounting the sealing and shearing means on the carrier arm whereby the sealing and shearing means is adapted to assume -a pivotal position for sealing the tensioned loop of strap on the article and for shearing the sealed loop of strap from the remaining supply of strap.

20. The strapping machine of cflaim -19 wherein the sealing means has a base adapted for engagement with the inner la-p of strap, and wherein the strapping unit further comprises a carrier arm operator for urging the carrier Iarm inwardly for clamping by said base the inner lap of strap against the article.

21. A strapping machine for binding with a tensioned strap comprising a stationary frame, a strapping unit mounted for longitudinal movement on the stationary frame, and means for shifting the strapping lunit longitudinally on the stationary frame between a retracted position and an extended strap-apply position; said strapping unit comprising `a `strap guideway for guiding the strap into a llaterally extending loop, aprincipal support pivotallly lconnected to the strap guideway for 4lateral pivotal movement, an auxiliary support pivotally mounted on the principal support for lateral -pivotal movement, strap feeding and tensioning means mounted on the auX- iliary `support adapted for feeding a free end of strap along the guideway and thereby form a loop of strap with overlapping portions and for subsequently withdrawing the strap for tensioning the loop about an :article encircled thereby, yand sealing means mounted on the auxili-ary support adapte-d for crimping a :strap seal onto the overlapping por-tions of the tensioned strap.

22. 'The strapping rnacln'ne of Claim 21 wherein the 16' strapping unit further comprises motor means operable for pivoting the princi-pal support on the strapping unit.

References Cited by the Examiner UNITED STATES PATENTS 12,561,169'. 7/ 51 Bickelhaupt 100-256 X 2,563,542 8/51 Mackeldui 53-198 X 2,797,634 7/57 Rueckert 100-13 2,801,507 8/57 Clauset a1. 53-'198 2,972,843 y2/6'1 Du Bro 53-198 X 3,019,577 2/62 Slamar et al. 53-74 3,179,037 4/ 65 Cranston et a1. y100--4 WALTER A. SCHEEL, Primary Examine-r. 

2. A STAPPING MACHINE FOR BINDING WITH A TENSIONED STRAP COMPRISING, A STATIONARY FRAME, STRAPPING UNIT MOUNTED FOR SUBSTANTIALLY VERTICAL LONGITUDINAL MOVEMENT ON THE STATIONARY FRAME, AND MOTOR MEANS FOR RAISING AND LOWERING THE STRAPPING UNIT ON THE STATIONARY FRAME BETWEEN RETRACTED AND STRAP-APPLYING POSITIONS; SAID STRAPPING UNIT COMPRISING A STRAP GUIDEWAY FOR GUIDING THE STRAP INTO A LATERALLY EXTENDING LOOP, STRAP FEEDING AND TENSIONING MEANS FOR FEEDING A FREE END OF STRAP FROM A SUPPLY THEREOF ALONG THE GUIDEWAY AND THEREBY FORM A LOOP AND FOR SUBSEQUENTLY WITHDRAWING THE STRAP FOR TENSIONING THE LOOP ABOUT AN ARTICLE ENCIRCLED THEREBY, SEALING AND SHEARING MEANS FOR SEALING THE OVERLAPPING PORTIONS OF THE TENSIONED STRAP AND FOR SHEARING THE SEALED LOOP OF STRAP FROM THE REMAINING SUPPLY OF STRAP, AND STRAP SUPPORT MEANS FOR LATERALLY GUIDING THE LOOP OF STRAP INWARDLY FROM THE GUIDEWAY INTO ENGAGEMENT WITH SAID ARTICLE, SAID STRAP SUPPORT MEANS BEING LATERALLY RETRACTABLE 